Known scan methods in magnetic resonance imaging include a scan method called 3D-FSPGR (Three-Dimensional Fast SPoiled GRadient echo). The scan method has a characteristic that it requires relatively long breath-holding of a subject. Another known scan method is one called 2D/3D-SSFP (Two-Dimensional/Three-Dimensional Steady State Free Precession). The scan method has a characteristic that it suffers from increased banding artifacts when a pulse sequence has a long repetition time TR. Accordingly, when any of these scan methods is used, it is necessary to set scan conditions such that the repetition time TR is as short as possible and consequently the scan time ST is reduced. Generally, the repetition time TR has strong dependency upon the bandwidth BW. In many cases, other parameters than the repetition time TR and bandwidth BW are set to specific values according to the purpose. Therefore, the operator should specify the other parameters than the repetition time TR and bandwidth BW, and then, optimize the bandwidth BW in order that the repetition time TR may be as short as possible.
Moreover, in the case that a large FOV (Field Of View) is defined for a subject having a large sized body or that reduced spatial resolution is applied to reduce the scan time ST for a subject who cannot hold his/her breath for a long time, it is necessary to successively optimize the value of the bandwidth BW during a real-time operation (see Abstract in Patent Document 1). The term real-time operation refers to a procedure of loading a site protocol and then modifying parameters on the spot. For example, a case may be assumed in which parameters should be modified after a patient has been laid over a table of an imaging apparatus in a hospital or the like. In this case, there is not enough time to modify parameters and no setting mistake is allowed, so that the procedure is highly difficult.
In optimizing the value of the bandwidth BW so that the repetition time TR is as short as possible as described above, the current operation involves the operator modifying the set value for the bandwidth BW while observing subsequent variation of the repetition time TR and/or scan time ST, and searching for an optimal specific value BWtr_min of the bandwidth BW to minimize these values.
Such an operation of manually searching for an optimal specific value BWtr_min of the bandwidth BW is, however, extremely cumbersome and significantly interferes with workflow.
By such circumstances, it is desired to provide a technique that facilitates optimization of the scan conditions, particularly, the value of the bandwidth BW, in a magnetic resonance apparatus.